135 lines
3.8 KiB
C
135 lines
3.8 KiB
C
/*
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IMGLIB: An example image loading library for use with SDL
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Copyright (C) 1999 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Sam Lantinga
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5635-34 Springhouse Dr.
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Pleasanton, CA 94588 (USA)
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slouken@devolution.com
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*/
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/* A simple library to load images of various formats as SDL surfaces */
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#include <stdio.h>
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#include <string.h>
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#include <ctype.h>
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#include "SDL_image.h"
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#define ARRAYSIZE(a) (sizeof(a) / sizeof((a)[0]))
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/* Table of image detection and loading functions */
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static struct {
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char *type;
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int (*is)(SDL_RWops *src);
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SDL_Surface *(*load)(SDL_RWops *src);
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} supported[] = {
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/* keep magicless formats first */
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{ "TGA", 0, IMG_LoadTGA_RW },
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{ "BMP", IMG_isBMP, IMG_LoadBMP_RW },
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{ "PNM", IMG_isPNM, IMG_LoadPNM_RW }, /* P[BGP]M share code */
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{ "XPM", IMG_isXPM, IMG_LoadXPM_RW },
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{ "XCF", IMG_isXCF, IMG_LoadXCF_RW },
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{ "PCX", IMG_isPCX, IMG_LoadPCX_RW },
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{ "GIF", IMG_isGIF, IMG_LoadGIF_RW },
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{ "JPG", IMG_isJPG, IMG_LoadJPG_RW },
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{ "TIF", IMG_isTIF, IMG_LoadTIF_RW },
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{ "PNG", IMG_isPNG, IMG_LoadPNG_RW }
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};
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/* Load an image from a file */
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SDL_Surface *IMG_Load(const char *file)
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{
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SDL_RWops *src = SDL_RWFromFile(file, "rb");
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char *ext = strrchr(file, '.');
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if(ext)
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ext++;
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return IMG_LoadTyped_RW(src, 1, ext);
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}
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/* Load an image from an SDL datasource (for compatibility) */
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SDL_Surface *IMG_Load_RW(SDL_RWops *src, int freesrc)
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{
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return IMG_LoadTyped_RW(src, freesrc, NULL);
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}
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/* Portable case-insensitive string compare function */
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int IMG_string_equals(const char *str1, const char *str2)
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{
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while ( *str1 && *str2 ) {
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if ( toupper((unsigned char)*str1) !=
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toupper((unsigned char)*str2) )
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break;
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++str1;
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++str2;
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}
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return (!*str1 && !*str2);
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}
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/* Load an image from an SDL datasource, optionally specifying the type */
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SDL_Surface *IMG_LoadTyped_RW(SDL_RWops *src, int freesrc, char *type)
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{
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int i, start;
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SDL_Surface *image;
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/* Make sure there is something to do.. */
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if ( src == NULL ) {
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return(NULL);
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}
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/* See whether or not this data source can handle seeking */
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if ( SDL_RWseek(src, 0, SEEK_CUR) < 0 ) {
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IMG_SetError("Can't seek in this data source");
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return(NULL);
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}
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/* Detect the type of image being loaded */
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start = SDL_RWtell(src);
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image = NULL;
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for ( i=0; i < ARRAYSIZE(supported); ++i ) {
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if( (supported[i].is
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&& (SDL_RWseek(src, start, SEEK_SET),
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supported[i].is(src)))
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|| (type && IMG_string_equals(type, supported[i].type))) {
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#ifdef DEBUG_IMGLIB
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SDL_printf("IMGLIB: Loading image as %s\n",
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supported[i].type);
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#endif
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SDL_RWseek(src, start, SEEK_SET);
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image = supported[i].load(src);
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break;
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}
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}
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/* Clean up, check for errors, and return */
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if ( freesrc ) {
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SDL_RWclose(src);
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}
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if ( i == ARRAYSIZE(supported) ) {
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IMG_SetError("Unsupported image format");
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}
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return(image);
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}
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/* Invert the alpha of a surface for use with OpenGL
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This function is a no-op and only kept for backwards compatibility.
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*/
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int IMG_InvertAlpha(int on)
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{
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return 1;
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}
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